Praise be to Allah the Lord of the Worlds.

Zakat is due on land purchased as trade commodity. The evidence on this is the following Hadith: Samurah bin Jundub (RAA) narrated that The Messenger of Allah (PBUH) used to command us to pay Zakah from (the goods) we had prepared for sale. {Related by Abu Dawud}. If the person buys and sells lands without waiting for their price to go up, then he must estimate their value according to their market price and pay (2.5%) as Zakat.

This is of course after their value reaches Nisab (Minimum amount liable for Zakat) and one lunar year elapses over possessing them. However, if he purchased land with the intention of selling it upon rise in price, then he must pay its Zakat for every lunar year, as is the view of the majority of the scholars. Moreover, he can`t delay payment of Zakat until price goes up, unless he doesn`t have enough cash to pay it. Therefore, once he sells the land, he must pay the Zakat due on it for every past lunar year, because it is a debt on him. As for the Maliki scholars, they are of the view that he must pay the Zakat for only one lunar year and upon selling that land. Ibn Roshd said: "One who purchases commodities with the intention of selling them upon rise in prices should pay their Zakat upon selling them." {Al-Mokhadimat Al-Momahidat, 1/285}.

In conclusion, following the view of the majority of scholars is safer as far as the teachings of Sharia are concerned. However, there is no sin in following the view of the Maliki scholars. And Allah the Almighty knows best.